I'm looking to get an air compressor for the garage, especially for working on the car. Not for a shop, just a home garage.

Please advise, the type of compressor to get and the minimum size, what to stay away from, etc.

1) Electric or gas, how many hp

2) Brands .. what sucks, what rocks

3) Capacity (how many gallons)

The reason I ask, Meijers has a Shop Force 2 gallon 1/3hp electric compressor (w/ accessories) for only $48.62 (regular $99.99). Seems rather cheap, which leads me to believe that it's pretty inadequate or unreliable .... but I'll let the org members that own air compressors be the judge.

Thanks!

 

i'd get a 5hp - ish, and at least a 20 gallon compressor, you'd be suprised how quickly u can empty a tank...

Also, I'd try to get a belt driven compressor, they tend to outlast the others.

 

Craftsmen
150 max psi
6 hp
30 gallon
forget the flow rates
does good. I wouldnt get anything smaller unless it has a very very high flowing compressor.

It's not necessary for a weekend mechanic, but it sure is handy.

 

I have a Campbell Hausfeld 5hp/125psi/15 gal which works pretty good. If I would be in the market again, I would look into a 15gal, 150psi Craftsman. Still, the CH was cheap and has no problem driving my impact wrench, cut off wheel, die grinder, etc. I even use it to winterize my sprinkler system in the fall. The compressor is the kind of item you want to get right the first time. I think 15 gal is large enough and is compact enough to transport if need be. Size being equal, a 150psi compressor will hold 20% more air than a 125psi.

 

That's what I have. I think it's a pretty good value, but there have been times when I needed a higher flowrate (cut off wheels and die grinders use more air than the compressor can supply, so you have to work and wait, work and wait). And the noise of the oil-less compressors is awful. I'm trying to justify getting a 240V, two-stage, intercooled and belt-driven upright with a 60 gallon tank. Ooooooooooohhhhhh yeeeeeeeeaaaaaahhhhhhh.

 

BTW, the CH can be had at Home Depot or Wal-mart. Usually $200 but sometimes it's on sale with a "starter kit" of accessories for $200.

At first I wanted a 30gal Craftsman but that thing is quite the behemoth and weights a ton!

 

The one you mentioned seems to be on the small side. If you only do one bolt every ten minutes then that would be fine but I have a 4 Gallon 5HP 140PSI Duo-something or other(its a friend but its in my garage) and it overheats during heavy use. Gas is totally not needed for a DIY'er. I recomend at least 3 Gallon. Also, as Stephen Max, a grinder eats up a ton of air. As supposed to an impact wrench that barely uses any. In fact, the air socket wrench I have seems to discharge the tank 3 times as fast as the impact.

 

CH brand 6.25 HP 28 gallon 150 PSi max here. Does anything I need it to do, and is still relatively portable at 150~ish pounds...

 

In the garage we have a Black Max 60 gal, 6 1/2hp compressor--WAY too small for our needs but would probably be perfect for you. I’ve recently been “privileged” to use a smaller 30gal compressor, and was disappointed in its performance. The “working and waiting” as described earlier was present at all times. (But that was working with a die grinder).

We’re currently searching for a new compressor also...looking at a two stage system, but trying to stay away from three phase power….maybe going with another 220.

What you need will vary, depending on your use…for airing up your tires, something small like you suggested will work fine. But running a ½” or even a ¾” impact needs a little more power.

--->Most compressors have charts on them with examples on the tools they can handle and how well the tools will perform..check those out, it will probably be more helpful in your decision.

 

OK What are you going to use it for?
If you plan on running tools that demand alot of air (CFM) NOT PSI! like: die grinder, cutting wheels, 1/2 impact. These tools require a CFM of 9.0 @ 90 psi or more.

I would go with a 220V model because it draws less amps and will cost you less to run. I have a 220 with a 60 gallon tank with dual compressor that is oil cooled. I forget the HP but that wii depend on the amout of CFM it put out.

Remeber that the high the CFM the lower the PSI.

This is what I found oin Home Depot site.

Owning an air compressor has its advantages. Air-powered tools allow you to work faster, more accurately and with less effort than with an electric or cordless counterpart, so you'll experience far less fatigue. Here are some popular uses for an air compressor:

Purpose
Typical Use

Inflating
Tires, ***** and rafts

Cleaning
Blow off work benches and lawn equipment, clean air filters

Nailing/Stapling
Frames, shingles, cabinets and trim

Cutting
Sheet metal, removing rusty bolts

Sanding/Grinding
Auto bodywork and woodworking

Painting
Auto bodywork, bicycles, fences and furniture

Spraying
Fertilizers and deck/fence wash

Air Tools
Drills, screwdrivers, ratchets, impact wrenches, etc.

Air Compressor Performance Terms
SCFM – Standard Cubic Feet per Minute. This is a measure of how much air a compressor can deliver or the amount of air required by a tool.
PSI – Pounds per Square Inch. Air pressure at which a tool operates.
Power – Type of energy needed to run a compressor. There are three types to choose from:
Standard household voltage (110 – 120 volts)
240 Voltage (heavy duty)
Gasoline engine for maximum portability

Cast Iron – Material used in some crankcases and cylinders to provide the longest life of all reciprocating air compressors

The Right Air Compressor for You
Decide how much air (SCFM) you will require.

Air requirements are based on the needs of the air tools you purchase.
Check the air requirements on the package of each tool.
Check the air delivery number on the compressor. The air delivery number on the compressor must be greater than the highest tool air requirement number to ensure proper use.
Decide how often you will use the compressor. A do-it-yourselfer may require a low cost, easy-to-maintain compressor, while a professional would require a compressor with a longer life and higher air delivery.

Advantages of Air Tools

Less expensive than electric and cordless equivalents
Can last longer because they run cooler than electric and cordless tools and are not exposed to overloading or stalling
Light weight makes use less fatiguing
No risk of fire or electric shock
Safety First
Be sure you have the correct electrical outlet to run the compressor (household or 240 volt). For outdoor use and maximum portability, you will need a compressor with a gas engine. Air compressors can be loud. It is a good idea to wear hearing protection when in use. Always exercise caution when using power tools. Follow the manufacturer's instructions for proper use and only use the tools for what they are intended. Consider safety equipment such as eye protection and/or respiratory protection depending on the project or job.

 

I have a Craftsman 33gal 6.5hp one. It's "oil free" and loud as hell! I do alot of wrenching on my Jeep(go figure) and cutting off spring perches was a PITA and took forever. Frozen bolts are a major problem for me and my cut off wheel gets alot of use.

If I had to do it over again I'd get a 220v 60gal upright from HF or Sears and call it good. Guy down the street has one and you can have a nornal conversation standing next to it unlike mine.

 

Oil free? Isn't oil meant to stop rusting within the tank and accesories. Thats another thing. Its much more convenient to have a self oiler than to have to put several drops into your tool every time you use it.

 

That is true, but what they are talking about is the oil in the compressor case. Kind of like engine oil in the crank case.

 

Whatever you do, DO NOT get one of the small 110V single-stage compressors. That's what I've got and the thing CONSTANTLY runs when I'm using even the impact wrench- let alone if I'm trying to grind or use my air ratchet.

my die grinder will completely empty the tank in about 30 seconds.. with the tank at full pressure, firing up the grinder will cause the compressor to kick on within 5 seconds.

To actually work in the same garage as the compressor, you will need earplugs- it's that loud. stay away.

If you want a compressor and plan on doing anything more than changing your tires with an impact, then I highly suggest you spend more than $300 on a compressor. you definitely get what you pay for in this case.

 

I got the 33 gallon compressor. Dont attempt to do body work with this nice size 33gal. It will run out of air in seconds. Just not enough air to keep up with some of the air tools to do body work.


20-33 gallons is fine to fix on cars, if your going to do body work get yourself a 60 plus gallon compressor so it doesnt run out of air so quick.

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=64003&item=3820608 034&rd=1&ssPageName=WDVW]Here you go

No Reserve either.

With a little work you'd be able to leave it on 24 7 and have more air than you'd ever need when ever you needed it.

 

If you're buying a new compressor anything under $320 you probably will not be happy in one way or another. As already mentioned get a oil cooled, belt driven compressor. Belt driven are the majic words. I've been looking for a compressor for a short while now, even though the new ones looked pretty I just couldn't afford them so I searched my local pawn shop, bargain trader magazine and eBay. Sometimes you can find a deal on eBay but the shipping would kill you, if you're lucky you might find one on eBay that's local to you.

A few days ago my search was completed, I found a local buyer. It's a older unit and it doesn't look so pretty but it's functional. I had to take it apart in order to get it home in the Max but I plan on shining it up. I'm not too sure on the tank capacity but I would say it's at least 25+ gallons. I also don't know the CFM's of the pump put it's a two cylinder pump so I'll happily assume it will flow decent air







The electric motor data plate

 

Thanks, I appreciate the feedback. This is all really good information, I'm sure there are many other people reading this too.

That 1150lb, 1991-manufactured, water-cooled compressor around Detroit is like, whoa!!!! Way too hardcore, someone elase should take it though

Candiman, how much? Looks nice.

 

very interesting thread since i was looking to get one myself pretty soon

 

The avg price I was seeing for a used compressor like this was $150-$200 depending on codition, I got mine for $80. Of course the price may vary in your city.

MIKE

 

thats what i got.. works great

 

It's going to take a while for that 1 hp motor to fill the tank, no matter how many cylinders you got. A two-stage compressor will develop good pressure, but ultimately the flowrate is determined by the motor.

 

To be honest with you I thought about that. During my re-search most of the compressors I was seing was between 3-5hp but I figured I'll give this a try. Just might be enough for my use. Once I get it up and running again I'll see how it operates.

MIKE

 

Update, took my brother to my job since they have a 60 gallon with two motors. In an hour and half he was able to sand 75% of his car. Sanded for 15 mins or less. Stopped for about 10 mins since he had to wait for the compressor to fill back up. The compressor did have two motors.

 

Another thing I wanted to compare was the amp rating of my 1hp motor to amp rating of todays motor based on 110 and 220 volts. My motor is very big for 1hp but I dont know how efficient it is. Todays 1hp motor is about 2/3 the size of my motor. As you can see my motor is rated at 13.6 amps @ 110V and 6.8 amps at 220V. If todays modern 3-5hp motors are rated the same amps as my 1hp motor of course it would be in my interest to swap out my motor for a stronger more efficient motor.

MIKE

 

Yes I was joking about the ebay listing, but the more I think about it... If it gets to the close and no one is bidding on it 350-400 bucks is a steal for that unit. Do a little work to it sinking maybe another 400 into it there is no reason you can't sell it for over 2g's unless there is something else wrong with it. Although I could see how it could be hard to move a unit like that with businesses not spending much now or buying new.

Rotary screw compressors are VERY quiet and put out a ton of CFM's. If anyone wants it, (JAY) if you pay to get it to Chicago I can get it to Atlanta for under $200.

 

pocketrocket, you also haven't said what kind of tools you're going to be using. You need to plan ahead. Look at the tools you plan to use and look at the CFM's those tools use, even if you haven't got the tool yet but plan on buying it you can get the info you need. Then buy a compressor that can supply the needed air. The size of the tank matters but not as much as you think, it the compressor can only supply 5CFM and the tool your using uses 8 then your going to be stopping often.

Jay, just because the compressor has 2 motors doesn't mean it puts out a lot of CFM, and if the rings are worn the it can't supply the rated CFM. Also there are many type of sanders out there, a standard 5k rpm sander olny uses about 6-7 CFM but some high-speed ones (15k+) can use upwards of 12. That's just average, continuous usage for either type is more like 22 CFM or more and that's if no one else is using air.
Most people won't see that kind of usage though.

 

I was just thinking, how is the flowrate of the pump determined by the motor. Is it because it takes X amount HP to push a pump with X amount of cfm's? A pump with less cfm's requires less power to operate, and visa versa?

MIKE

 

5. WHAT MOTOR HORSEPOWER DO YOU REQUIRE?


Horsepower is directly proportional to the CFM rating of a compressor; typically, the higher the horsepower the more air (CFM) the compressor can produce. Don't rely solely on horsepower or attempt to buy the highest horsepower compressor you can afford. Let you CFM and PSI requirements determine horsepower for you. Be very careful with the compressors that claim high horsepower ratings, with low air flow performance, this often indicates a consumer-oriented air compressor. These products are designed with the motor operating at maximum speed which typically results in a motor that will run hot, with a severely shortened life span.


HOW TO SELECT AN AIR COMPRESSOR


Under normal conditions, this information should provide a satisfactory compressor selection guide. Unusual operating conditions can require a larger unit than calculated. When in doubt, select a larger unit to insure adequate initial capacity and provide for future expansion.
1. Add up the air requirements for all the air operated devices the compressor will be required to operate. If manufacturer's data is not available for these devices, the table below may be used as a reference guide. Enter cfm amount on line A of chart. Determine the maximum pressure (PSIG) required, enter on line B.
2. Add 10% for air system leaks and/or future growth. This factor is shown on line C.
3. Multiply line A by line C and enter ACFM requirement on line D.
4. For 6-8 hours per day operation using a reciprocating air compressor, a proper load factor for cooling and extended service life is required. To accomplish this, multiply line D by 1.15 and enter this amount on line E and size air compressor accordingly.
5. For continuous operation, use a Rotary Compressor. Choose the Rotary compressor which delivers a flow and pressure rate equal to or greater than the ACFM and PSIG found on line D and B respectively.

AIR COMPRESSOR SELECTION CHART

A__________________ ACFM_____________________
B__________________ PSIG_____________________
C__________________x 1.10____________________
D__________________ ACFM required____________
___________________x 1.15____________________
E__________________(size recip. machine for this capacity)


Referenced from: Ingersoll-Rand

Main page: http://www.air.ingersoll-rand.com/index.asp

 

Hold on Big Daddy that info is way and beyond what a avg. do-it-yourselfer will ever need for selecting a compressor for his home. If I ever open a auto shop I'll keep that link handy.

I don't know if others got the info you were trying to rely but I sure didn't. I just wanted Stephen to clearify his post a little.

MIKE

 

BTW I have a 3-phase 208v dual stage intercooled 5hp unit attached to an 80gal tank and runs at 175psi. It produces 16.5 CFM. It's at work and doesn't see much use but it's there when I need it. I got it for a song.
When we moved into the warehouse the company that was there before us went BK. I got this, a fork lift, nice wood desk w/credenza, wood table and 2 leather chairs for 2G's. I rebuilt the compressor myself and it's run great since.

For a good home unit I'd check the newspaper and look for a good use one.

 

I know I was

I think this is perfect for the typical home DYI'er.
SPEEDAIRE

 

The 30 gal upright is great. I put it in the crawl space under the laundry room,
then I ran copper pipe for 5 drop points. Cant even hear it and it takes up no room in the garage

 

It takes power to create flow at a particular pressure. Th electrical analogy is current at a particular voltage, and the mechanical analogy is a force at a particular velocity (in this case velocity is analogous to flow, and force is analogous to pressure). I thought 777's articled was pretty good, but I have a technical background. He makes a very good point that you should look at the standard cfm at 40 psi and at 90 psi the compressor is capable of producing and compare it to the flow requirements of the tools you will be using to determine if a compressor is suitable. Don't just go by horsepower claims alone.

Sounds like your 3 phase unit is everything a man would want.

 

http://www.sears.com/sr/javasr/produ...seBVCookie=Yes
this one is nice i have it at my parent house i can run two tools at they same time with no problem